<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
		<script>
			
			function validateForm(){
				var x=document.forms["myForm"]["fname"].value;
				if(x==null || x==""){
					alert("需要输入名字！");
					return false;
				}
			}
		</script>
	</head>
	<body>
		<form name="myForm" action="" onsubmit="return validateForm()" method="post">
			名字：<input type="text" name="fname"/>
			<input type="submit" value="提交" />
		</form>
	</body>
</html>
